Various types of automatic arpeggio controls for keyboard electronic musical instruments have been heretofore proposed. The automatic arpeggio plays the notes of a chord in an up or down sequence, repeating the sequence in successively higher or lower octaves of the instrument. The notes of the arpeggio chord can progress either upwardly from the lowest note of the lowest octave to the highest note of the highest octave, or progress down from the highest note of the highest octave to the lowest note of the lowest octave. The arpeggios can be made continuous and the time interval between arpeggio notes can be controlled to control the rhythm. Most known automatic arpeggio systems are designed for beginners or relatively unskilled musicians. A standard chord is selected by pushing a corresponding one of a plurality of buttons, rather than allowing the musician to key the individual notes of the chord in conventional manner. The arpeggio control is usually completely separate from the standard keyboard of the instrument.
A selectable note arpeggio system is described in U.S. Pat. No. 3,854,366. The arpeggio system therein described requires a completely separate control circuit for detecting and assigning the notes used for the arpeggio chord from that used by the instrument for generating tones in the standard manner in response to the playing of the keyboard.